ICN (Information-Center Network), as a new-model network architecture proposed in recent years with an attempt to replace the conventional TCP/IP protocol-based network architecture, has become a new hot issue in researches on next generation network architecture. The ICN adopts an information-centered communication mode instead of existing end-to-end communication modes. In this mode of the ICN, the importance of data location is diminished; the ICN focuses on data content per se rather than physical logic.
NDN (Named Data Networking) is one of important representatives of the ICN. The NDN includes two kinds of data structures: an interest packet and a data packet, wherein the interest packet is for a data requester to request data in the network, and the data packet refers to the data returned from a data owner upon receipt of the request, i.e., the data packet is a response to the interest packet. The NDN is a pull-based architecture, wherein a consumer requests data by sending an interest packet, while the corresponding data packet is returned along the original path. In this way, a good content distribution function is achieved through a built-in data caching function and a flexible forwarding policy layer.
During an entire communication process of the NDN, a router needs to maintain the following table structures to implement its functions: Content Store (CS), Pending Interest Table (PIT), and Forwarding Information Base (FIB). As shown in FIG. 1, upon receiving the interest packet, the router first checks the CS; if relevant content is found, the content will be directly returned; otherwise, the PIT will be checked; if a relevant record is matched in the PIT, an interface for the interest packet to access will be added to PIT entries; otherwise, a new entry is created and the interest packet is forwarded based on the FIB.
A forwarding policy is a decision basis in the forwarding process in the NDN. Unlike a conventional IP network in which a routing layer is responsible for various functions while forwarding policy that decides whether to forward the interest packet, when to forward, and where to forward, wherein the FIB is a main basis for the forwarding process. The FIB comprises a name prefix and an interface list, which may be expressed as <Prefix, face1, face2, . . . , facen>. The NDN forwarding process adopts a longest prefix matching, and one interest packet may be forwarded out from a plurality of interfaces.
In the prior art, BestRoute is a core forwarding policy in the NDN, where the policy classifies forwarding interfaces into three categories according to their capabilities of obtaining a data packet, which are represented by green, yellow and red, respectively. To forward an interest packet, the green forwarding interface ranking top is selected in priority, and the yellow forwarding interface is a secondary choice; the red forwarding interface represents that the forwarding interface is invalid and cannot be used for forwarding. As the network status changes, the statuses of forwarding interfaces will also be shifted from one another. For example, a forwarding interface in a green state will be shifted to a yellow state in the case of being idle for a long time. This policy has a good adaptability to network statuses, but the shifts among the forwarding interfaces in red, yellow, and green statuses are very inflexible, such that this policy lacks a certain sensitivity, which easily causes overuse of an optimum forwarding interface; consequently, load equilibrium cannot be well achieved.